3.4 Analysis And Synthesis Flashcards

1
Q

What is another name for a positive ion?

A

A cation

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3
Q

What is the method for a flame test?

A

Nichrome wire is cleaned by repeatedly placed in hydrochloric acid
Dip the wire in more hydrochloric acid and into the compound to be tested
Place in the Bunsen flame and see what colour is produced from the compound

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4
Q

What are the tests for positive ions?

A

Flame test

Reaction with sodium hydroxide

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5
Q

What is the flame test for lithium?

A

Crimson (red)

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6
Q

What is the flame test for sodium?

A

Yellow

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7
Q

What is the flame test for potassium?

A

Lilac

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8
Q

What is the flame test for calcium?

A

Red

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9
Q

What is the flame test for Barium?

A

Green (pale)

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10
Q

What is the flame test for copper?

A

Green

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11
Q

What is the precipitate colour when you react sodium hydroxide and Aluminium?

A

White

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12
Q

What is the precipitate colour when you react sodium hydroxide and calcium?

A

White

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13
Q

What is the precipitate colour when you react sodium hydroxide and magnesium?

A

White

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14
Q

What is the precipitate colour when you react sodium hydroxide and copper?

A

Blue

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15
Q

What is the precipitate colour when you react sodium hydroxide and iron II?

A

Green

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16
Q

What is the precipitate colour when you react sodium hydroxide and iron III?

A

Brown

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17
Q

What is another name for a negative ion?

A

Anion

18
Q

What ions are tested for in tests for negative ions?

A
Carbonate
Sulfate
Chloride
Bromide
Iodide
19
Q

What is the test and the result for carbonate ions?

A

Add hydrochloric acid

It fizzes giving off CO2 (use limewater to check)

20
Q

What is the test and the result for sulfate ions?

A

Add hydrochloric acid then barium chloride solution

A white precipitate is formed

21
Q

What is the test and the result for chloride, bromide and iodide?

A

Add nitric acid then silver nitrate

Chloride - White precipitate
Bromide - Cream precipitate
Iodide - Yellow precipitate

22
Q

What does Aluminium do?

A

The only precipitate that dissolves in excess sodium hydroxide solution

23
Q

What is titration used for?

A

A neutralisation reaction
Acid + alkali -> salt + water

The volumes of the solutions that react exactly can be found

24
Q

What is the method for titration?

A

Fill the burette with acid to the zero mark
Measure the alkali using a pipette then put into a conical flask
Add 3-4 drops of universal indicator to the alkali (pink colour)
Add the acid a few drops at a time until the solution is almost colourless
Drop-wise add 1 at a time until solution is completely colourless
Record the volume of acid needed for neutralisation (end point reached)
Repeat and take average result

25
Q

In titration calculations what is the equation?

A

Moles = concentration x volume

Moles: mol
Concentration: mol/dm3
Volume: dm3

26
Q

How do you convert to decimetres?

A

Cm3 divided by 1000

27
Q

At neutralisation…

A

Moles of acids are equal to moles of alkali

28
Q

In chemical analysis what is a qualitative method?

A

Finds out if a substance is in a sample

29
Q

In chemical analysis what is a quantitive method?

A

Finds out how much of a substance is in a sample

30
Q

What are the advantages of instrumental methods?

A

Quick
Accurate
Only a small sample size needed

31
Q

What are the disadvantages of instrumental methods?

A

High equipment cost
Needs frequent calibration
Specialist knowledge needed to operate

32
Q

What are just qualitative methods?

A

Mass spectrometry- provides RFM
Atomic absorption spectrometry - absorbs light to reveal the energies needed to excite an electron to another energy level

33
Q

What are qualitative and quantitive methods?

A

Gas chromatography - separates a mixture of components into individual components
Infra-red spectrometry - identifies particular covalent bonds in a molecule